x/crypto/ssh/terminal: ReadPassword broken on windows

[Joshua-Anderson]

On go1.4.2 windows/amd64 with golang.org/x/crypto/ssh/terminal revision 56474dfd625f18739b46f075b138fd0133717491.

ReadPassword seems to be broken.

Reproduction Case:

package main

import (
  "fmt"
  "golang.org/x/crypto/ssh/terminal"
)

func main() {
  fmt.Print("password: ")
  password, err := terminal.ReadPassword(0)

  if err != nil {
    fmt.Println(err)
  }

  fmt.Println(string(password))
}

When I run this code on Windows 10, ReadPassword() throws the following error: The handle is invalid.

The same code works on linux and osx.

[ianlancetaylor]

Does it work if you use terminal.ReadPassword(syscall.Stdin) ?

The fact that 0 == syscall.Stdin on Unix system does not mean that that holds true on Windows.

[Joshua-Anderson]

You're correct, I made the mistake of assuming that syscall.Stdin was 0 on windows. I never considered that it would be different on windows (silly windows), and the docs on stdin were a little misleading. Thank you for the clarification!

[ianlancetaylor]

A lightly edited note from @cadethacker:

There are actually two reason this might be caused.

The first is documented above and correct that the handle ids on Windows are not the same as Unix.

But the second reason is…. if you are using Cygwin/mintty/git-bash on Windows, those Windows shells are unable to reach down to the OS API, and will throw the exact same error of the “handle is invalid”.

This issue is not directly fixable and really not an issue with Go. If you switch to Powershell or even CMD then executing ReadPassword will work as expected. You may then switch back to your shell for all other commands that don’t invoke ReadPassword. If you must stay in Cygwin/minty/git-bash then take a look at https://github.com/rprichard/winpty project, it might solve your issue.